Effects of Low Salt Plus Upright Posture, Angiotensin II, ACTH, and Potassium upon Plasma Renin Activity, Aldosterone, and Cortisol

Abstract

In order to study the control system of plasma aldosterone in human, we examined the effects of low salt plus upright posture, angiotensin II, ACTH and potassium upon plasma renin activity, aldosterone and cortisol in five subjects who were supposed to be normal. All of the procedures, low salt diet with below 3 g of salt and 2 hr-upright posture, 0.25 mg of Cortrosyn, angiotensin infusion to increase 20mmHG of diastolic pressure for an hour, and 30 mEq of potassium infusion stimulated plasma aldosterone significantly. Furthermore, in each subject the degrees of response to each of these stimulations were almost same. In an old woman aged 68, responses to all of stimulations were significantly lower than those in other subjects. Plasma cortisol was significantly stimulated by ACTH, but slightly reduced by potassium infusion. From these results, it is certain that plasma aldosteron levels are easily affected by a small amount of changes in angiotensin, ACTH, potassium and sodium. However, responses of aldosterone to these changes seem to be decreased in old subjects.

Characterization of NCI-H295R Cells as an In Vitro Model of Hyperaldosteronism

“…Interestingly, potassium stimulation led to a relative decrease in cortisol output. Overall, potassium induced eff ects on adrenal glucocorticoid secretion are not well defi ned and clearly infl uenced by species-, cell-and context-( in vivo vs. in vitro ) dependent mechanisms with examples of potassium induced increased [ 18 ] , decreased [ 19 ] , or unchanged [ 20 ] glucocorticoid levels. While aldosterone output could be stimulated to some extent by ACTH and angiotensin II, incubation with high levels of potassium was followed by a pronounced, specifi c and exclusive shift towards mineralocorticoid production, as exemplifi ed in a multisteroid analysis.…”